1. Field of the Invention
This invention relates to a connector examination device. In particular, the connector examination device examines a connector having metal terminals inserted therein and determines whether or not there is an electrical connection established between the metal terminals. The connector examination device also detects the inserted condition of metal terminals in a connector housing and an improper attachment of metal terminals inserted into a connector housing.
2. Related Art
Generally, a connector assembly comprises a connector housing constructed of a synthetic resin. Metal terminals, secured to ends of wires, are inserted in the housing. When a metal terminal is inserted into a proper insertion position, the metal terminal is retained against withdrawal by a lance or retaining pawl provided on the metal terminal or the connector housing. In a connector of this type, if the metal terminal is not attached in the proper insertion position, so that it is not retained against withdrawal by the lance, the possibility exists that the metal terminal can be withdrawn during use. Therefore, it is necessary to first check for a proper insertion and correct the insertion if it is improper.
Previously, a conventional method has been used to check for proper insertion. A retainer is used in combination with lances. The retainer engages a metal terminal inserted into the proper position and cooperates with the lance to form a double retaining means. Before the metal terminals are inserted, the retainer is initially retained at a position where it will not interfere with the insertion of connector and the metal terminals. The metal terminals are inserted and the retainer is moved into a completely retained position to engage the metal terminals.
If any one of the metal terminals fails to reach the properly inserted position, so that it is disposed in an improper inserted position, the retainer is caught by the metal terminal during movement of the retainer into the completely retained position, so the retainer can not be moved into the completely retained position.
Therefore, by determining whether or not the retainer can be moved into the completely retained position, it can also be ascertained whether or not the metal terminals have been inserted to the proper position. If it is determined that the metal terminal has not been inserted to the proper position, the metal terminal insertion operation is carried out again.
In this conventional method, the retainer, fit in the completely retained position, is not removed from the connector and the connector must be used with the retainer fit into the connector. Therefore, an equal number of retainers and connector housings are required. Thus, the number of the component parts is unnecessarily high, which in turn creates a high cost.
Furthermore, the retainer only determines whether or not any improperly inserted metal terminal exists. If it is determined that there exists an improperly inserted metal terminal, the metal terminal must be pushed deeper into the connector or the insertion of the metal terminal must be carried again to correct the position of the terminal. The insertion condition of the metal terminals must be re-checked. Therefore, much time and labor is required. Further, if the metal terminal is disposed in an improper position near to the proper inserted position, it can not be clearly and readily determined from the appearance alone if the metal terminal is in an improper position. Thus, the position of all of the metal terminals must be corrected. Particularly, in the case of a multi-pole connector having many metal terminals, the correction of all the terminals requires much time and labor to correct the position of the metal terminals. Therefore, the problem that the efficiency of the metal terminal insertion operation is low has been encountered.
Previously, there have been proposed various kinds of connector examination devices for detecting incomplete insertion of metal terminals. One example of a known connector examination device is shown in FIG. 22. In this device, lance check pins 206 extend and oppose lances 203 in a connector 201. Each lance check pin 206 is inserted into a lance flexure space 204 formed in a connector housing 202. If a metal terminal 205 is completely inserted into a proper position, when the lance check pin 206 is inserted into the lance flexure space 204, it does not abut against the lance 203. The lance check pin 206 advances to a position beneath the lance 203, as shown in FIG. 23. If the metal terminal 205 is in an incomplete inserted condition, the lance check pin 206 abuts against the front end portion of the lance 203 projected substantially into the lance flexure space 204 and elastically deforms. In this arrangement, the lance 203 projects substantially into the lance flexure space 204. Because of the improper attachment of the metal terminal 205, the lance check pin 206 abuts against the front end of the lance 203. Hence, the lance check pin 206 can not move to the position beneath the lance 203. As a result, the insertion of the metal terminal 205 is incomplete.
In this conventional connector, the lance 203 has a large thickness so that it has an elastic restoring force and a strength for retaining the metal terminal against withdrawal. A metal terminal support portion 208, which is provided between the lance flexure space 204, and a cavity 207, which receives the metal terminal 205, need to have only sufficient strength to maintain the positioning of the metal terminal 205. Therefore, the thickness of the support portion 208 is less than the thickness of the lance 203. Even when the metal terminal 205 is completely inserted in the proper position, the lance 203 projects slightly toward the lance flexure space 204 beyond the metal terminal support portion 208.
The thickness of a front end portion 206a of the lance check pin 206 is less than the inner dimension of the lance flexure space 204 so that the front end portion 206a can be positioned beneath the lance 203. When the lance check pin 206 is initially inserted into the lance flexure space 204, a gap forms between the front end portion 206a of the lance check pin 206 and the metal terminal support portion 208.
However, in the known device described above, the lance check pin 206 can be inserted into the lance flexure space 204, with its front end portion 206a bent or deformed and the lance check pin 206 obliquely advances in the space 204. In this case, even if the metal terminal 205 is completely inserted into the proper position, with the lance 203 retracted from the lance flexure space 204, the front end portion 206a of the lance check pin 206 abuts against the portion of the lance 203 extending into the lance flexure space 204, as shown in FIG. 24. As a result, even though the metal terminal 205 is disposed in the proper position, the front end portion 206a of the lance check pin 206 can not be brought into the position beneath the lance 203. As a result, a wrong determination that the metal terminal 205 is in an incompletely attached condition is possible.
Another example of known devices is disclosed in Japanese Utility Model Examined Publication No. 62-47093. In this device, a connector holder for holding a connector in a predetermined position is provided with lance check pins projected in an opposed relation to lances in the connector. Each of the lance check pins extends toward an associated lance flexure space. Each lance check pin contacts the front end of the lance disposed in a lance flexure space when an associated metal terminal is in an improperly inserted position. In this device, if a metal terminal is improperly attached, so the lance is disposed in the lance flexure space, the lance check pin abuts against the front end of the lance when the connector is set in the connector holder. The connector can not be properly set in the connector holder. Thus, the improper attachment of the metal terminal can be determined.
In the above device, however, if the connector is forced into the connector holder, though the metal terminal is disposed in an improperly attached condition, the front end of the lance check pin abuts against the lance with a force large enough that a lance made of a synthetic resin is deformed. When deformation occurs, not only is the improper attachment of the metal terminal undetected, but the lance is also damaged. Thus, the connector is rendered unusable.